Optic neuropathy associated with cryptococcal arachnoiditis in AIDS patients

Approach to Neurologic Complications in the Immunocompromised Patient

Neurologic complications are common in immunocompromised patients, including those with advanced human immunodeficiency virus, transplant recipients, and patients on immunomodulatory medications. In addition to the standard differential diagnosis, specific pathogens and other conditions unique to the immunocompromised state should be considered in the evaluation of neurologic complaints in this patient population. A thorough understanding of these considerations is critical to the inpatient neurologist in contemporary practice, as increasing numbers of patients are exposed to immunomodulatory therapies. In this review, we provide a chief complaint-based approach to the clinical presentations and diagnosis of both infectious and noninfectious complications particular to immunocompromised patients.

Cryptococcal meningitis presenting as acute flaccid paralysis: A case report

Cryptococcus is a cosmopolitan fungus with tropism for the nervous system and a higher prevalence of infection in immunosuppressed patients. Neurological compromise caused by this microorganism mainly debuts as a meningeal syndrome (headache, fever, neck stiffness) with predominant encephalic involvement. In this report we present the rare case of a non-HIV patient with flaccid paralysis and peripheral nerve involvement due to crytpococcal meningitis. This is a 53-years-old woman, with a past-medical history of diabetes, who presented with dysarthria, unilateral peripheral facial paralysis, asymmetric ascending quadriparesis, generalized hyporeflexia and urinary retention. Neuroimaging was initially reported as negative for vascular or demyelinating diseases. Electrophysiological studies were performed, and acute flaccid paralysis of undetermined etiology was defined as a temporal clinical diagnosis. Cerebrospinal fluid molecular analysis confirmed the presence of Cryptococcus neoformans var. gatti; posteriorly, antifungal treatment with amphotericin B and fluconazole was started. Polyneuroradiculopathy symptoms significantly improved over the in-hospital stay. In conclusion, spinal cord and peripheral nerve involvement by Cryptococcus is an infrequent cause of acute flaccid paralysis that should be considered in the differential diagnosis even in HIV-negative patients.

Update on the application of optic nerve sheath fenestration

BACKGROUND

With the ongoing development of surgical procedures and instruments, the safety of optic nerve sheath fenestration (ONSF) has been improved.

OBJECTIVE

Through the past three decades, progress has been made in preventing visual loss from chronic optic nerve swelling in idiopathic intracranial hypertension (IIH), secondary intracranial hypertension and local optic nerve diseases. We now review the updated application of ONSF in those diseases.

METHODS

The application of ONSF in papilledema due to IIH, secondary intracranial hypertension to cerebral venous sinus occlusion, Cryptococcal meningitis, and intracranial mass or tumors is reviewed. Additionally, the potential benefits of ONSF in local optic neuropathy from optic nerve sheath meningioma, optic nerve drusen, traumatic optic neuropathy and optic nerve/sheath biopsy are also described.

RESULTS

Although ONSF has little or no effect on intracranial pressure, it is a safe, relative easy and effective surgical procedure to prevent or reverse visual loss in IIH. When other treatment modalities fail to timely protect vision, ONSF can be useful in protecting visual function or delay visual loss in secondary intracranial hypertension.

CONCLUSION

We recommend that ONSF should be considered as a meaningful alternative or an adjunct therapy to reduce or delay the visual morbidity of these diseases, although the use of ONSF for some of them remains controversial.

Cryptococcal meningitis in AIDS

Cryptococcal meningitis remains a significant cause of morbidity and mortality amongst patients living with human immunodeficiency virus (HIV). The prevalence in the developed world has decreased as HIV is being diagnosed earlier, but is still significant, and the prevalence in resource-limited settings is exceedingly high. The presenting symptoms usually include a headache, fever, and, less often, cranial nerve abnormalities. Space-occupying lesions do occur, but are rare. Once diagnosed, patients should be treated with a combination of amphotericin and flucytosine, with step-down therapy to fluconazole for a minimum of a year, or until the CD4 count is above 100 cells/μL, whichever is longer. In the acute phase of treatment increased opening pressure is common, which should be managed aggressively with frequent lumbar punctures, or through neurosurgical interventions (lumbar drains, ventriculoperitoneal shunts) if those fail. Antiretrovirals should be delayed at least 2 weeks, but maybe as many as 10 weeks, after initiation of antifungal therapy in order to prevent clinical or subclinical immune reconstitution inflammatory syndrome (IRIS), which may lead to increased mortality. However, if IRIS does develop, there is no role for antiretroviral interruption, and the condition should be managed supportively by use of anti-inflammatories and aggressive management of elevated opening pressure, if present. Steroids should be administered for specific indications only (IRIS or cryptococcoma with cerebral edema and risk of herniation) as routine use of steroids increases mortality in cryptococcal meningitis.

Visual loss in HIV-associated cryptococcal meningitis: A case series and review of the mechanisms involved

Permanent visual loss is a devastating yet preventable complication of cryptococcal meningitis. Early and aggressive management of cerebrospinal fluid pressure in conjunction with antifungal therapy is required. Historically, the mechanisms of visual loss in cryptococcal meningitis have included optic neuritis and papilloedema. Hence, the basis of visual loss therapy has been steroid therapy and intracranial pressure lowering without clear guidelines. With the use of high-resolution magnetic resonance imaging of the optic nerve, an additional mechanism has emerged, namely an optic nerve sheath compartment syndrome (ONSCS) caused by severely elevated intracranial pressure and fungal loading in the peri-optic space. An improved understanding of these mechanisms and recognition of the important role played by raised intracranial pressure allows for more targeted treatment measures and better outcomes. In the present case series of 90 HIV co-infected patients with cryptococcal meningitis, we present the clinical and electrophysiological manifestations of Cryptococcus-induced visual loss and review the mechanisms involved.

Infectious optic neuropathies: a clinical update

Different forms of optic neuropathy causing visual impairment of varying severity have been reported in association with a wide variety of infectious agents. Proper clinical diagnosis of any of these infectious conditions is based on epidemiological data, history, systemic symptoms and signs, and the pattern of ocular findings. Diagnosis is confirmed by serologic testing and polymerase chain reaction in selected cases. Treatment of infectious optic neuropathies involves the use of specific anti-infectious drugs and corticosteroids to suppress the associated inflammatory reaction. The visual prognosis is generally good, but persistent severe vision loss with optic atrophy can occur. This review presents optic neuropathies caused by specific viral, bacterial, parasitic, and fungal diseases.

Visual evoked potentials show strong positive association with intracranial pressure in patients with cryptococcal meningitis

OBJECTIVE

To verify the relationship between intracranial pressure and flash visual evoked potentials (F-VEP) in patients with cryptococcal meningitis. Method The sample included adults diagnosed with cryptococcal meningitis admitted at a reference hospital for infectious diseases. The patients were subjected to F-VEP tests shortly before lumbar puncture. The Pearson’s linear correlation coefficient was calculated and the linear regression analysis was performed.

RESULTS

Eighteen individuals were subjected to a total of 69 lumbar punctures preceded by F-VEP tests. At the first lumbar puncture performed in each patient, N2 latency exhibited a strong positive correlation with intracranial pressure (r = 0.83; CI = 0.60 - 0.94; p < 0.0001). The direction of this relationship was maintained in subsequent punctures.

CONCLUSION

The intracranial pressure measured by spinal tap manometry showed strong positive association with the N2 latency F-VEP in patients with cryptococcal meningitis.

Early clinical and subclinical visual evoked potential and Humphrey's visual field defects in cryptococcal meningitis

Cryptococcal induced visual loss is a devastating complication in survivors of cryptococcal meningitis (CM). Early detection is paramount in prevention and treatment. Subclinical optic nerve dysfunction in CM has not hitherto been investigated by electrophysiological means. We undertook a prospective study on 90 HIV sero-positive patients with culture confirmed CM. Seventy-four patients underwent visual evoked potential (VEP) testing and 47 patients underwent Humphrey's visual field (HVF) testing. Decreased best corrected visual acuity (BCVA) was detected in 46.5% of patients. VEP was abnormal in 51/74 (68.9%) right eyes and 50/74 (67.6%) left eyes. VEP P100 latency was the main abnormality with mean latency values of 118.9 (±16.5) ms and 119.8 (±15.7) ms for the right and left eyes respectively, mildly prolonged when compared to our laboratory references of 104 (±10) ms (p<0.001). Subclinical VEP abnormality was detected in 56.5% of normal eyes and constituted mostly latency abnormality. VEP amplitude was also significantly reduced in this cohort but minimally so in the visually unimpaired. HVF was abnormal in 36/47 (76.6%) right eyes and 32/45 (71.1%) left eyes. The predominant field defect was peripheral constriction with an enlarged blind spot suggesting the greater impact by raised intracranial pressure over that of optic neuritis. Whether this was due to papilloedema or a compartment syndrome is open to further investigation. Subclinical HVF abnormalities were minimal and therefore a poor screening test for early optic nerve dysfunction. However, early optic nerve dysfunction can be detected by testing of VEP P100 latency, which may precede the onset of visual loss in CM.

Ocular complications of cryptococcal meningitis in patients with HIV: report of two cases and review of the literature

AIDS-related cryptococcal meningitis can result in significant vision loss, but the risk factors, prognostic features, and optimal management of patients with ocular complications is unknown. We present 2 cases of blindness associated with cryptococcal meningitis and review the literature for associated cases. Twenty-six additional cases of vision deterioration or loss as a result of HIV-associated cryptococcal meningitis were reviewed. Irreversible and complete loss of vision occurred in 14 patients (50%). Permanent vision loss was more likely to occur in patients with ocular symptoms and neurologic signs at presentation. Nearly all patients with permanent visual loss experienced blindness within the first week after hospital admission. Visual complications are not uncommon in cryptococcal meningitis, and once vision loss occurs, it is often irreversible regardless of control of infection or intracranial pressure. Visual complaints in cryptococcal meningitis should be considered a potentially poor prognostic sign.

Optic nerve sheath fenestration in cryptococcal meningitis

A patient with acquired immunodeficiency syndrome (AIDS) developed crytpococcal meningitis, complicated by papilledema and severe progressive visual loss despite medical therapy. Bilateral optic sheath fenestration resulted in significant improvement in vision and resolution of papilledema. Histopathologic evaluation of the optic nerve sheath demonstrated numerous cryptococci. Optic nerve sheath fenestration may be an effective treatment method when high intracranial pressure is contributing to visual loss, even in the presence of involvement of the optic nerve sheath by the fungus.

Infectious optic neuropathy

A wide variety of infectious agents are known to cause optic neuropathy. This article will consider the bacteria, spirochetes, fungi, and viruses that most commonly affect the optic nerve. Clinical presentation is variable, but some pathogens often produce a characteristic funduscopic pattern. Diagnosis is usually made on the basis of clinical suspicion and serologic testing. Polymerase chain reaction is also increasingly utilized. Most infectious agents can be effectively treated but visual recovery is highly variable.

Perineural Metastasis of Breast Cancer Treated With Optic Nerve Sheath Fenestration

A 36-year-old woman with bilateral optic neuropathy and orbital and central nervous system metastasis from breast carcinoma developed progressive bilateral vision loss with severe optic disc swelling. She underwent optic nerve sheath fenestration of the left eye resulting in modest improvement in vision and resolution of disc edema. Optic nerve sheath fenestration is a known treatment for papilledema, but its effectiveness as a treatment for an optic neuropathy caused by perineural or intrasheath metastasis is less clear. Optic nerve sheath fenestration should be considered as a treatment option for an optic neuropathy caused by perineural or intrasheath metastasis, especially in cases where alternative treatments are not tolerated and visual loss is severe at presentation.

Cryptococcal disease and HIV infection

In the era of highly active antiretroviral therapy for the treatment of HIV infection, the dramatic reductions in mortality and morbidity associated with immune reconstitution have included a marked decline in the incidence of opportunistic infections. Cryptococcus neoformans is a yeast that causes predominantly neurological disease in immunocompromised individuals, in particular those with HIV infection. It continues to be an important diagnosis in developing areas and amongst late presenters in parts of the world with access to highly active antiretroviral therapy. This article reviews the epidemiology, clinical features and management of cryptococcal disease in HIV-infected patients, particularly focusing on the history of, current guidelines for and future developments in antifungal therapy.

Presumed multifocal cryptococcol choroidopathy prior to specific systemic manifestation

PURPOSE

Disseminated cryptococcosis is a major cause of morbidity and mortality in immunocompromised individuals, especially those with the acquired immunodeficiency syndrome (AIDS). Early diagnosis and treatment greatly improves the outcome, so clinical clues that lead to prompt diagnosis are important.

METHODS

Three patients with AIDS in whom multifocal choroiditis and choroidal lesions were the initial signs of disseminated cryptococcosis were treated with systemic amphotericin B and flucytosine. All of the patients had a systemic work-up that included evaluation of the cerebral spinal fluid (CSF).

RESULTS

All three patients who were seen with the choroidal lesions as the presenting sign were noted to have either positive titers for cryptococcus or cultures that grew cryptococcus in the CSF. The choroidal lesions are presumed to be due to cryptococcus as no histopathologic or microscopic studies were available for ocular tissues. The choroidal lesions started to resolve one to three months after systemic treatment with amphotericin B and flucytosine.

CONCLUSION

Primary choroidal lesions in patients with AIDS may herald severe systemic disseminated disease. Funduscopic examination, however, may detect disseminated cryptococcal disease before other overt clinical manifestations, thereby allowing prompt institution of effective therapy.

Visual loss in immunocompetent patients with Cryptococcus neoformans var. gattii meningitis

In Papua New Guinea cryptococcal meningitis occurs predominantly in immunocompetent patients in whom Cryptococcus neoformans var, gattii is implicated in 95% of cases. Ocular complications are common. We have reviewed ophthalmic findings in 82 immunocompetent patients and have attempted to identify those features of the disease that predict an unfavourable visual outcome. Visual loss occurred in 52.6% of survivors and was associated with optic atrophy following optic disc swelling in 60.9%. Progression of disc swelling to optic atrophy was predicted by the presence of an abducens palsy (P = 0.049) and cerebrospinal fluid (CSF) cryptococcal antigen titres > 1:1024 (P = 0.036). Raised intracranial pressure (defined as opening CSF pressure > or = 300 mm on admission) was not associated with visual loss. Vision deteriorated in 17.3% of patients despite anticryptococcal therapy and in 3.7% it followed curative therapy. The high rate of visual loss in immunocompetent patients with C. neoformans var. gattii infection contrasts with others' experience of immunosuppressed patients with C. neoformans var. neoformans infection, in whom visual loss was rare. This difference may reflect immune mediated optic nerve dysfunction in C. neoformans var. gattii meningitis caused by either compression due to arachnoid adhesions or oedema and inflammatory cell-mediated damage.

Ophthalmic manifestations of infections with Cryptococcus neoformans in patients with the acquired immunodeficiency syndrome

The present study was undertaken to determine the nature and the prevalence of ophthalmic manifestations of infections with Cryptococcus neoformans in human immunodeficiency virus seropositive patients and to analyze whether the presence or absence of ocular signs is associated with improved survival. Eighty human immunodeficiency virus seropositive patients with cryptococcal infection were enrolled. We observed papilledema in 26 of the 80 patients (32.5%). Visual loss and abducens nerve palsy occurred in seven patients (9%). Only two patients (2.5%) had optic atrophy. Visual loss caused by optic nerve involvement was less frequent among the 62 patients treated with oral conazoles exclusively than among the 18 patients who had received amphotericin B or a combination of amphotericin B and conazoles. Actual invasion of the intraocular structures with Cryptococcus neoformans was an uncommon complication in our series. In addition to the ocular manifestations attributable to cryptococcal disease, human immunodeficiency virus-related retinopathy was present in nearly half of the patients. Cytomegalovirus retinitis was diagnosed in four patients (5%). The 26 patients (32.5%) with papilledema had a median survival of 182 days vs 160 days for the patients without papilledema. The median survival for 18 patients (22.5%) with cotton-wool spots was 102 days vs 186 days for those without cotton-wool spots. The differences between these subgroups were not statistically significant.

Bilateral optic nerve cryptococcosis in sudden blindness in patients with acquired immune deficiency syndrome

PURPOSE

A neuroanatomic study was undertaken to search for the cause of sudden, simultaneously bilateral blindness in a patient with acquired immune deficiency syndrome who had cryptococcal meningitis.

METHODS

Careful gross examination was performed, and microscopic sections were cut at 50- to 100-microns intervals of the entire visual pathway.

RESULTS

Focal cryptococcosis destroyed segments of the right intracanalicular optic nerve and the left intraorbital optic nerve adjacent to the optic canal. The meninges were heavily infiltrated by Cryptococcus organisms around the optic tracts, optic nerves, and optic chiasm; however, only a few scattered cryptococcal organisms were found in the periphery of the chiasm contiguous with heavy meningeal infection. Blood vessels supplying the chiasm appeared normal. Generalized cerebral edema and focal vacuolization of periventricular white matter were evident.

CONCLUSION

The authors believe that sudden, simultaneously bilateral visual loss in this patient was caused by focal but fulminant necrosis of both optic nerves. However, the presence of cryptococcal organisms throughout the basal meninges and in the sheaths of both optic nerves suggests that cryptococcosis may produce visual loss by damaging multiple areas of the anterior visual pathway.

Optic nerve sheath decompression for visual loss in patients with acquired immunodeficiency syndrome and cryptococcal meningitis with papilledema

Visual dysfunction developing in association with acquired immunodeficiency syndrome (AIDS) can be multifactorial. Two patients with this syndrome and cryptococcal meningitis had papilledema and visual loss. Both were treated by optic nerve sheath fenestration. One patient had bilateral nonsimultaneous optic nerve sheath fenestrations; visual function improved in one eye. The other patient had bilateral visual improvement after a unilateral optic nerve sheath fenestration. Cryptococcal organisms were present in the dural sheath specimens of both patients despite ongoing therapy with antifungal medication. Postoperative orbital infectious complications did not occur. Autopsy examination of one patient showed that the sites of fenestration were patent. Medical treatment of cryptococcal meningitis associated with AIDS has a guarded prognosis. Optic nerve sheath fenestration offers a treatment alternative for papilledema and visual loss that occur with cryptococcal meningitis.

[Evoked potentials in HIV infection]

The study of the literature data on the multimodal evoked potentials in HIV infected patients shows many abnormalities as well in asymptomatic subjects without AIDS as in AIDS subjects with or without neurological signs. Visual evoked potentials (VEPs) reveal prolonged P100 wave latency in 22% of HIV asymptomatic subjects and in 26% of HIV symptomatic subjects; brainstem auditory evoked potentials (BAEPs) reveal an increase of the interpeak latency I-V in 16% of asymptomatic subjects and in 32% of symptomatic subjects; somatosensory evoked potentials (SEPs) by median nerve stimulation reveal prolonged central conduction time in 6% of asymptomatic subjects and in 11% of symptomatic subjects; somatosensory evoked potentials (SEPs) by tibial nerve stimulation reveal prolonged central conduction time in 4% of asymptomatic subjects and in 45% of symptomatic subjects; motor evoked potentials (MEPs) by magnetic stimulation reveal prolonged central motor conduction time in 46% of asymptomatic subjects.

Raised intracranial pressure and visual complications in AIDS patients with cryptococcal meningitis

The clinical course of cryptococcal meningitis in AIDS shows some important differences from the features of the illness in non-AIDS patients. Complications such as raised intracranial pressure and visual impairment that are recognised in non-AIDS patients may be less frequent in those with AIDS. Persistent intracranial hypertension should be managed actively to prevent visual impairment. In AIDS patients, in whom ventriculo-peritoneal shunts carry additional risks, acetazolamide can be used successfully to lower the CSF pressure and prevent visual loss.

Medical management of AIDS patients. Bacterial and fungal infections

The rapid and thus far generally inexorable rise in HIV infections has led to a series of opportunistic infection that includes those caused by bacteria, yeasts, and members of the Eumycetes. The infections range in prevalence from occasional to highly prevalent, in severity from trivial to fatal, and in anatomic areas involved from local to disseminated. They occur as isolated, concurrent, or sequential infections with regard to other opportunistic diseases. Some vary in their geographic distribution. They may be newly acquired or reactivated and occur early or late in the course of HIV infection. Bacterial infections are usually easily treated, although they frequently disseminate and often recur after seemingly appropriate treatment. In contrast, all but the mildest fungal infections are difficult to treat and even more difficult or impossible to eradicate. The diagnosis of bacterial and fungal infections begins with clinical suspicion and involves relatively standard methodology. Treatment of the systemic mycoses and some bacterial infections in HIV infected patients is punctuated by exaggerated side effects of therapy, frequent relapses, and the need for maintenance suppressive therapy.

Morphometric Comparisons of Optic Nerve Axon Loss in Acquired Immunodeficiency Syndrome

Axonal degeneration and diminution of the axonal population in the optic nerve have been documented in aging and in various neuro-ophthalmic conditions. We applied morphometric techniques to the postmortem examination of optic nerves obtained from patients with acquired immunodeficiency syndrome. Twelve optic nerves (eight from patients with AIDS and four from age-matched control eyes) were stained with paraphenylenediamine and morphometrically analyzed with a computer-assisted image and measurement system. Degeneration was often severe and was scattered throughout all of the AIDS-affected optic nerves. In the AIDS-affected optic nerves, the mean axonal population was markedly lower than the mean obtained from normal optic nerves (880,000 vs 1,507,000). Despite the approximate 40% loss of axons, mean axonal diameters were not markedly different, suggesting that no particular class of axon was especially susceptible to AIDS-associated degeneration. The extent and pattern of axonal loss in optic nerves of patients with AIDS suggest that the changes may not only be secondary to damage at the retina, but may reflect an AIDS-associated primary optic neuropathy.